1. Field of the Invention
The present invention relates to a multiple image display device that has a plurality of image display devices and that displays a single image and to image display devices that constitute a multiple image display device.
2. Description of the Related Art
In recent years, the screens of image display devices have become increasingly larger. In particular, not only is the screen of an image display device increased in size, but also there is provided an image display device in which a plurality of image display devices are combined together to offer a larger screen (hereinafter referred to as a multiple image display device).
The image display devices that constitute such a multiple image display device are each provided with a display portion (for example, a liquid crystal panel) and a housing portion (hereinafter, a bezel portion) that is placed around the display portion and that produces no display. Since the bezel portion is present, the screen of the multiple image display device is divided into a plurality of portions, with the result that the screen becomes noncontinuous.
One of the problems resulting from the noncontinuous screen will be described with reference to FIG. 11. FIG. 11 is a schematic diagram showing an example of a conventional multiple image display device. FIG. 11 shows a case where a single input image 100 is divided into four portions and where the portions of the divided image are displayed, as they are, by the multiple image display device 110 incorporating four image display devices 110a to 110d. The multiple image display device 110 is configured by combining the image display devices 110a to 110d together, two in a horizontal direction and two in a vertical direction. “Displaying them as they are” means that, when two portions of the image that are displayed with the bezel portion 111 interposed therebetween are disposed side by side, they become continuous.
As shown in FIG. 11, when the four portions of the divided image are displayed, as they are, on the image display devices 110a to 110d, the image is distorted. For example, as shown in FIG. 11, when a perfect circle is displayed without being displayed on the bezel portion 111, the circle is divided by the bezel portion 111, and the width of the bezel portion 111 is inserted. This causes the perfect circle, as a whole, to be formed in the approximate shape of an ellipse, with the result that the displayed image becomes distorted.
On the other hand, an example of a multiple image display device that prevents a displayed image from becoming distorted is shown in FIG. 12. FIG. 12 is a schematic diagram showing an example of a conventional multiple image display device. As in FIG. 11, FIG. 12 shows a case where the four portions obtained by dividing the input image 100 are displayed on four image display devices 120a to 120d. In the multiple image display device 120, a bezel portion 121 is considered to be a region where display can be achieved, and the image is displayed accordingly. In particular, the divided image is enlarged and parts of it are also assigned on even the bezel portion 121. Since the parts of the image assigned on the bezel portion 121 are not actually displayed, they are represented by broken lines in FIG. 12. As shown in FIG. 12, the use of the multiple image display device 120 reduces the image distortion shown in FIG. 11.
However, in the multiple image display device 120 shown in FIG. 12, the parts of the image are also assigned on the bezel portion 121 in the perimeter thereof (in the example shown in FIG. 12, the left and right edge portions thereof). Specifically, the edge portions of the input image 100 and the bezel portion 121 overlap each other, and thus the edge portions are not displayed. Unlike the middle portion of the input image 100, the edge portions of the input image 100 are relatively difficult to estimate from the adjacent portions of the image. Thus, when the edge portions of the input image 100 are not displayed on the screen, the image is significantly difficult to recognize.
Moreover, in a case where the multiple image display device 120 is used as a display of, for example, a personal computer, when a GUI (graphical user interface) such as a mouse pointer is placed on an edge portion of the input image 100 and is not displayed, the operability is significantly degraded. In particular, as compared with the case where the GUI is hidden on the bezel portion in the middle portion, the GUI hidden on the bezel portion in the edge portion is more unlikely to be found by a user, with the result that it is difficult to recognize.